Invertebrate predation on egg masses of the European cuttlefish, Sepia officinalis: An experimental approach

Abstract

Sepia officinalis embryos develop inside ink-stained black encapsulated eggs fixed to the seafloor in shallow water habitats. The enveloping layers of these eggs allow the embryo to develop within a micro-environment and are thought to provide protection.Since embryological development may last months, this short-lived species spends a relatively long period of its lifespan on shallow waters, vulnerable to predation and physical stress. Yet, only a handful of species are known to feed on S. officinalis eggs, most of them fish. Marine benthic invertebrates, however, are likely candidates contributing to predation of this critical life stage. In this study, several invertebrate marine species, from 6 different phyla and with diverse feeding habits, were investigated as potential predators of S. officinalis eggs under laboratory conditions.Feeding experiments also tested to what extent the egg capsule and lower levels of mechanical protection could deter predation and Multivariate Correspondence Analyses were performed to explore which feeding traits of the tested invertebrate species would explain the experimental results. Results showed predation on eggs by crabs and echinoderms equipped with certain prey capture methods that allowed them to feed on eggs. Also, the egg capsule appeared to provide protection from predation by certain species with less powerful prey capture tools. Prey capture tools of the tested species appeared to be the feeding trait that better explained the experimental results. Therefore, whether or not eggs were eaten in these experiments might be determined by a mechanical factor. Nonetheless this may not be the case for species that might not have fed on eggs due probably to a chemosensory question, not recognising them as food.This work thus contributes to the understanding of the ecology of early life stages of cuttlefish and the factors that can affect offspring survival and subsequently impact recruitment to the adult populations of this exploited species.iii ACKNOWLEDGMENTS This work might not have been possible without the support and help of many people.Many thanks to my directors, Fernando Fernández-Álvarez and Dr. Roger Villanueva, who taught me with patience and trusted me to embark on this study, while making the work truly feel like a journey of curiosity. Without their continuous guidance and encouragement this work would not have been the same.

Field observations on the behavioural ecology of the stout bobtail squid Rossia macrosoma (Cephalopoda: Sepiolidae) from Scottish waters

“…6e-g). Although most sea urchins are considered herbivorous, some species exhibit an omnivorous or even carnivorous diet (Baumiller 2008;Crook and Davoren 2016), and three species have been shown to prey upon cephalopods eggs (Martins et al 2018). While in narrow crevices these predators are restrained from getting to sepiolids eggs due to their physical size, we have evidence that if the eggs are accessible, they will be preyed upon by sea urchins (Fig.…”

Environmental estrogen exposure disrupts sensory processing and nociceptive plasticity in the cephalopod, Euprymna scolopes

“…In both behavioral assays, effects were most pronounced in hatchlings, with juveniles showing behavior more consistent with those of unexposed squid. Defensive behaviors in the hatchling stage are vitally important for cephalopods, which are under strong predation pressure both before and after hatching (Martins et al, 2018). In E. scolopes, the initial first few weeks of hatchling life are characterized by high mortality due to poor hunting success, which likely compounds predation risk through increased time spent hunting (Hanlon et al, 1997) Example traces from a 1 s application of a von Frey filament are shown for sham and injured squid.…”

A review of recent studies on the life history and ecology of European cephalopods with emphasis on species with the greatest commercial fishery and culture potential

“…It was concluded that the use of an endoscope, visual implant elastomer and swabbing could provide all necessary information without causing negative effects. Martins et al (2018) showed that at least ten different invertebrate species (Bolinus brandaris, Cancer pagurus, Dardanus arrosor, Homarus gammarus, Callinectes sapidus, Squilla mantis, Echinus melo, Cidaris sp., Paracentrotus lividus, Astropecten aranciacus) feed on cuttlefish egg masses. The authors suggest that the invasive blue crab Callinectes sapidus should be considered as a new threat for cuttlefish in North East Atlantic waters.…”